The commander of NATO-led forces in Afghanistan met with the army chiefs of Pakistan and Afghanistan in Islamabad Sunday to discuss border security and anti-terror coordination.

The meeting of the Afghanistan-Pakistan-ISAF Tripartite Commission came as Pakistani civilian and military leaders are preparing for talks Tuesday on ending the nearly six-month blockade of NATO supply routes into Afghanistan, following a NATO air strike last November that mistakenly killed 24 Pakistani soldiers.

The meeting, the first in nearly a year, is a key component of the international community's engagement in Afghanistan and has offered the opportunity for discussion on issues of tactical, operational and strategic importance.

The ISAF commander, U.S. General John Allen, said he was â€œvery encouragedâ€ by the talks with Pakistani General Ashfaq Parvez Kayani, and Afghan General Sher Muhammad Karimi.

General Allen said â€œthere was agreement these meetings are important to achieving continued progress toward our shared goals of a peaceful, stable, and prosperous Afghanistanâ€ so the country â€œcan no longer be a safe haven for terrorists again.â€

After the deadly NATO air strike, already tense U.S.-Pakistani ties plunged into a diplomatic deadlock. Pakistani officials demanded an unconditional apology. But Washington refused and Islamabad retaliated by cutting off NATO ground supply routes to international forces in Afghanistan. In return, the U.S. withdrew as much as $3 billion of promised military aid.

Islamabad also demanded an end to drone strikes, arguing they are counter-productive because they kill civilians, exacerbate anti-U.S. sentiment and violate sovereignty.

Washington says the strikes are crucial to defeating al-Qaida and the Taliban.